SIMULTANEOUS DETECTION OF TWO ANTIGENS USING AN ELECTROCHEMICAL IMPEDANCE SPECTROSCOPYBASED APTASENSOR

Abstract

COVID-19, caused by SARS-CoV-2, has resulted in significant mortality since its emergence in 2020, while tuberculosis, caused by Mycobacterium tuberculosis, is another respiratory infection with a high incidence level worldwide. The COVID-19 pandemic significantly burdened the healthcare system, resulting in an 18% decrease in newly diagnosed tuberculosis cases in 2021 and an increased incidence rate in the subsequent year. The common diagnostic tools for these infections are either low-sensitive, costly, or slow. Considering the possible comorbidities and health complications, this project proposes the development of a novel dual electrochemical impedance-based aptasensor for the simultaneous detection of COVID-19 and tuberculosis (Fig. 1). The proposed detection system has several advantages, such as time and resource efficiency due to the simultaneous detection and cost efficiency due to the use of aptamers, the synthetic oligonucleotides with high affinity towards an analyte. Moreover, high sensitivity was achieved for this aptasensor with the LOD for MPT64 being 0.2415 pg/ml (9.15 fM) and the LOD for S glycoprotein being 0.3261 pg/ml (12.99 fM) in the optimal conditions, which are a 10-minute protein incubation time and 2 μM aptamer concentration. The further optimization of the conditions, such as a wider range of incubation time intervals, blocking and stabilization steps improvements, as well as testing a wider range of protein concentrations for sensitivity, can potentially improve the results.